It is desirable to be able to detect the status of a machine and/or a process run on the machine e.g. mechanical conditions and defects in moving parts of a machine, e.g. bearings of a rotating machine, especially for large and heavy machines like refiners used for the treatment of fiber material in connection with the manufacture of paper or board, in order to avoid emergency stops in the production. An early detection of the developing of defects also allows better planning of maintenance and cost effective service on the machine. Unnecessary stops in the production are avoided thus maximizing the production.
WO 9613011 a technique is described for determining different “footprints” for vibration data of a machine before the machine is taken into actual operation. These footprints are determined for different operation conditions of the machine. In later operation of the machine vibrations are monitored by comparison of sensed vibration data with footprints stored for the operation condition in question of the machine.